改进功能“hex”

function hex(x){
    return isNaN(x) ? "00" : hexDigits[x >> 4] + hexDigits[x & 0xf];
    // or option without hexDigits array
    return (x >> 4).toString(16)+(x & 0xf).toString(16);
}

嗨，这是我的解决方案后，获得元素的颜色与Javascript

function rgb_hex(rgb_string_js){ //example: "rgb(102,54,255)"
  var new_rgb_list = rgb_string_js.replace("rgb(","").replace(")","").split(",");
  return ("#" + parseInt(new_rgb_list[0]).toString(16) + parseInt(new_rgb_list[1]).toString(16) + parseInt(new_rgb_list[2]).toString(16)); 
}

函数返回以十六进制表示的元素的背景色。

function getBgColorHex(elem){
    var color = elem.css('background-color')
    var hex;
    if(color.indexOf('#')>-1){
        //for IE
        hex = color;
    } else {
        var rgb = color.match(/\d+/g);
        hex = '#'+ ('0' + parseInt(rgb[0], 10).toString(16)).slice(-2) + ('0' + parseInt(rgb[1], 10).toString(16)).slice(-2) + ('0' + parseInt(rgb[2], 10).toString(16)).slice(-2);
    }
    return hex;
}

使用的例子:

$('#div1').click(function(){
   alert(getBgColorHex($(this));
}

斯菲德尔

和@Jim F答案一样，但是使用ES6语法，所以指令更少:

const rgb2hex = (rgb) => {
  if (rgb.search("rgb") === -1) return rgb;
  rgb = rgb.match(/^rgba?\((\d+),\s*(\d+),\s*(\d+)(?:,\s*(\d+))?\)$/);
  const hex = (x) => ("0" + parseInt(x).toString(16)).slice(-2);
  return "#" + hex(rgb[1]) + hex(rgb[2]) + hex(rgb[3]);
};

var hexDigits = new Array
        ("0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"); 

//Function to convert rgb color to hex format
function rgb2hex(rgb) {
 rgb = rgb.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);
 return "#" + hex(rgb[1]) + hex(rgb[2]) + hex(rgb[3]);
}

function hex(x) {
  return isNaN(x) ? "00" : hexDigits[(x - x % 16) / 16] + hexDigits[x % 16];
 }

(源)

全案例(rgb, rgba, transparent…等)解决方案(coffeeScript)

 rgb2hex: (rgb, transparentDefault=null)->
    return null unless rgb
    return rgb if rgb.indexOf('#') != -1
    return transparentDefault || 'transparent' if rgb == 'rgba(0, 0, 0, 0)'
    rgb = rgb.match(/^rgba?\((\d+),\s*(\d+),\s*(\d+)(?:,\s*(\d+))?\)$/);
    hex = (x)->
      ("0" + parseInt(x).toString(16)).slice(-2)

    '#' + hex(rgb[1]) + hex(rgb[2]) + hex(rgb[3])